EP0704050B1 - Determining metallic material fatigue or integrity of a joint by measuring damping factors - Google Patents
Determining metallic material fatigue or integrity of a joint by measuring damping factors Download PDFInfo
- Publication number
- EP0704050B1 EP0704050B1 EP94909835A EP94909835A EP0704050B1 EP 0704050 B1 EP0704050 B1 EP 0704050B1 EP 94909835 A EP94909835 A EP 94909835A EP 94909835 A EP94909835 A EP 94909835A EP 0704050 B1 EP0704050 B1 EP 0704050B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- metallic material
- damping factor
- transducer
- fatigue
- vibration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
- G01H1/12—Measuring characteristics of vibrations in solids by using direct conduction to the detector of longitudinal or not specified vibrations
- G01H1/16—Amplitude
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/11—Analysing solids by measuring attenuation of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/12—Analysing solids by measuring frequency or resonance of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/0055—Generation of the force using mechanical waves, e.g. acoustic
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0073—Fatigue
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0688—Time or frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0235—Plastics; polymers; soft materials, e.g. rubber
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/025—Change of phase or condition
- G01N2291/0258—Structural degradation, e.g. fatigue of composites, ageing of oils
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02827—Elastic parameters, strength or force
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/10—Number of transducers
- G01N2291/101—Number of transducers one transducer
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/267—Welds
Definitions
- the inventor herein has succeeded in developing a method for determining the fatigue of a metallic material, a metallic material fatigue determining device, and a metallic joint integrity determining device - claims 1, 8, 11.
- the technique is of measuring the damping factor of a discrete piece of metallic material, such as a part in an assembly or the like, and using that damping factor for determining the fatigue integrity of that part either by comparing it with a standardized damping factor or with previously measured damping factors for the same part.
- the part might be a single piece of material, or it might be a welded or otherwise joined piece of material and the test may be one for integrity, i.e.
- damping factor measurement may be made periodically to determine the part's increasing fatigue. This technique may be used to identify parts which are need of replacement prior to any chance of catastrophic failure.
- damping factor measurement of a discrete piece of metallic material might be used to good advantage.
- an impulse of energy may be applied to the part, such as by striking it with a blunt object or the like, and the induced vibration in the part measured by a transducer which converts the vibration into an electrical signal for input to a computer.
- a computer may then easily make the appropriate calculation from the induced vibration to determine the damping factor.
- the damping factor of a part vibrating at its natural frequency may be determined by comparing peak amplitudes of successive cycles of the vibration.
- a continuous input of energy may be provided to the part instead of an impulse of energy.
- a frequency generator may be coupled to a transducer, such as a speaker, shaker, or other such device, and the frequency generator tuned or adjusted so as to sweep through the range of the lowest natural frequencies of the part.
- a transducer such as a speaker, shaker, or other such device
- the frequency generator tuned or adjusted so as to sweep through the range of the lowest natural frequencies of the part.
- the damping factor may be readily calculated by measuring the half-power bandwidth of a cycle and dividing it by the center frequency, as is well known in the art. Using either of these methods, a vibration is induced in the part and the response thereto is measured from which the damping factor is determined.
- One of the advantages of using the inventor's method of inducing a vibration in the part is that it is believed that the part need not be isolated and may be tested in place. This eliminates disassembly of the part from any larger assemblage which dramatically reduces any costs involved in using the present method in determining the damping factor. This provides great advantages over other prior art methods which require disassembly and isolation of the part to be tested, such as in the x-ray method. Furthermore, the device used to implement the method disclosed herein may be relatively compact, readily portable, and sufficiently small such that the testing of many differently sized parts which might be otherwise relatively difficult to access may be readily tested.
- the inventor's first technique for measuring relative fatigue in a part includes the step of inducing a vibration in the part desired to be measured, such as by striking the part 20 with a blunt instrument such as a rod 22 to thereby induce vibrations in the part 20.
- a vibration in the part desired to be measured such as by striking the part 20 with a blunt instrument such as a rod 22 to thereby induce vibrations in the part 20.
- the opposite ends of the part 20 may be supported by a pair of supports 24, 26, although this is not believed to be necessary.
- a transducer 28 measures the induced vibration and produces an electrical output which is amplified by an amplifier 30 and then input to a computer 32 for calculation of the damping factor.
- the vibration induced by the input of an impulse of energy into the part 20 may have a varying amplitude or force level.
- the damping factor may be readily calculated by comparing the amplitudes of successive cycles of vibration induced by any one of these force levels. As shown in Figure 2, the intensity of the blow to the part does not affect the measurement of the damping factor as the damping factor is determined by comparing two successive peak amplitudes, regardless of the size thereof. Whether the initial amplitude has an intensity of a, b, or c, there is no variation in the measured damping factor. Instead, the damping factor is determined solely by the characteristics of the part 20.
- the part 20 may in actual fact be comprised of a pair of elements 34, 36 which are joined by a weld 38 or the like. If that is the case, then the integrity of the weld 38 may be readily determined by the measurement of the damping factor.
- the joint, shown in Figure 1 as weld 38 may be any other joint or connection and its integrity similarly measured through the methodology disclosed herein.
- an alternate technique for measuring the damping factor and, hence, material fatigue may be used.
- the vibration in the part 20 is picked up by a transducer 28 for converting the sensed vibrational signals to an electrical signal which is then amplified by an amplifier 30 for input to a computer 32.
- the initial energy input to the part 20 is achieved by way of a frequency generator 40 which produces an electrical output at a particular frequency which is then amplified by a power amplifier 42 and fed to a second transducer 44, which may be a speaker or shaker or other such device, which is coupled to the part 20.
- the frequency generator 40 is then tuned to frequencies sweeping through the range of the lowest natural frequencies of the part 20 to thereby produce a continuous vibrational response therein as shown in Figure 4.
- a peak amplitude F c of one of the several natural harmonics induced in the part 20 is chosen for measurement of the damping factor.
- the damping factor is equal to the half power bandwidth ⁇ F, or F2 - F1, divided by the center frequency F c .
- F1 and F2 the half power frequencies, are those frequencies at which the amplitude is .707 times the maximum amplitude.
- the existence of a crack 46 would affect the vibrational response of the part 20 and, hence, the damping factor measured with the inventor's technique, thereby becoming detected for suitable correction thereto.
- damping factor may be conveniently used to determine the damping factor of a particular part.
- the damping factor may be periodically measured for a particular part to develop a history thereof and thereby be used to monitor the developing fatigue in the part as an aid to deciding when it should be replaced or repaired.
- the damping factor measured by the techniques disclosed and claimed herein could be used by comparing them with standardized damping factors for similar kinds of metals and parts.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Acoustics & Sound (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
Abstract
Description
Claims (12)
- A method for determining the fatigue of a metallic material, said method comprising the steps of:measuring the damping factor of said metallic material by inducing a vibration material by inducing a vibration in said metallic material, anddetermining the damping factor of said metallic material from its measured dynamic response to said vibration; andcomparing said measured damping factor with another damping factor, the difference therebetween being indicative of the fatigue of said metallic material.
- The method of Claim 1 further comprising the steps of:repeating said steps at spaced time intervals in the same metallic material to thereby determine a plurality of damping factors; andcomparing said plurality of damping factors to thereby determine the change in fatigue of said metallic material over time.
- The method of Claim 2 wherein the metallic material has a weld therein and further comprising the step of determining the integrity of said weld by comparing said plurality of damping factors.
- The method of Claim 1 wherein said another damping factor is a standardized damping factor.
- The method of Claim 1 wherein the step of inducing a vibration includes the step of introducing an impulse of energy by physically striking said metallic material.
- The method of Claim 1 wherein the step of measuring includes the steps of:coupling a transducer means (28) to said metallic material;inputting the output of said transducer means to a computer (32); andwherein the step of comparing the damping factors includes the step of using the computer to calculate said comparisons.
- The method of claim 1 wherein the step of inducing a vibration includes the step of continuously exciting said metallic material with energy oscillating at substantially the natural frequency of said metallic material.
- A metallic material fatigue determining device comprising a transducer (28) for coupling to said metallic material, said transducer being configured to measure the vibrational response of said metallic material, and a programmed electronic machine (32) connected to said transducer and being configured to calculate the damping factor of said metallic material from the vibrational response thereof, said damping factor being representative of the fatigue thereof.
- The device of Claim 8 further comprising a device for inducing a vibration in said metallic material comprising a hard object (22).
- The device of Claim 8 further comprising a device for introducing a continuous stream of energy into said metallic material at substantial its own natural frequency comprising a frequency generator (40) whose output is connected to a speaker (44), said speaker being coupled to said metallic material.
- A metallic joint integrity determining device comprising a transducer (28) for coupling to one side of said joint (38), said transducer being configured to measure the vibrational response across said joint, and a programmed electronic machine (32) connected to said transducer and being configured to calculate the damping factor of said joint from the vibrational response thereof, said damping factor being representative of the integrity thereof.
- The device of Claim 11 further comprising a device (20, 40, 44) for introducing a vibration across said joint.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/025,940 US5476009A (en) | 1993-03-03 | 1993-03-03 | Method and apparatus for determining material fatigue by measuring damping factors |
US25940 | 1993-03-03 | ||
PCT/US1994/002172 WO1994020826A1 (en) | 1993-03-03 | 1994-03-01 | Method and apparatus for determining material fatigue by measuring damping factors |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0704050A4 EP0704050A4 (en) | 1995-11-21 |
EP0704050A1 EP0704050A1 (en) | 1996-04-03 |
EP0704050B1 true EP0704050B1 (en) | 1998-08-26 |
Family
ID=21828894
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94909835A Expired - Lifetime EP0704050B1 (en) | 1993-03-03 | 1994-03-01 | Determining metallic material fatigue or integrity of a joint by measuring damping factors |
Country Status (9)
Country | Link |
---|---|
US (2) | US5476009A (en) |
EP (1) | EP0704050B1 (en) |
JP (1) | JPH08507378A (en) |
AT (1) | ATE170287T1 (en) |
AU (1) | AU6252094A (en) |
CA (1) | CA2157364A1 (en) |
DE (1) | DE69412829T2 (en) |
ES (1) | ES2123125T3 (en) |
WO (1) | WO1994020826A1 (en) |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
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US5402781A (en) * | 1993-03-03 | 1995-04-04 | Washington University | Method and apparatus for determining bone density and diagnosing osteoporosis |
US5652386A (en) * | 1993-03-03 | 1997-07-29 | Washington University | Method and apparatus for predicting sturctural integrity by estimating modal damping factor |
US5476009A (en) * | 1993-03-03 | 1995-12-19 | Washington University | Method and apparatus for determining material fatigue by measuring damping factors |
US5594178A (en) * | 1994-11-08 | 1997-01-14 | Asahi Glass Company Ltd. | Strength evaluation method for brittle material pieces |
EP0770867A1 (en) * | 1995-10-23 | 1997-05-02 | INPRO Innovationsgesellschaft für fortgeschrittene Produktionssysteme in der Fahrzeugindustrie mbH | Method for quality testing of semi-products, modules and components with ultrasounds |
US5836891A (en) * | 1997-05-20 | 1998-11-17 | Dimarogonas; Andrew D. | Method and apparatus for determining the density and structural integrity of biological tissues, medical implants and structural parts |
US6035715A (en) * | 1997-09-15 | 2000-03-14 | Entela, Inc, | Method and apparatus for optimizing the design of a product |
US6233530B1 (en) * | 1997-09-15 | 2001-05-15 | Entela, Inc. | Control system for a failure mode testing system |
US6247366B1 (en) | 1997-09-15 | 2001-06-19 | Alexander J. Porter | Design maturity algorithm |
WO2001031350A1 (en) * | 1999-10-26 | 2001-05-03 | Entela, Inc. | Control system for a failure mode testing system |
KR100463727B1 (en) * | 2002-04-11 | 2004-12-29 | 백수곤 | The Method and Device of the Reliability Test and Decision |
CA2393522C (en) * | 2002-07-15 | 2005-05-17 | Saskatchewan Research Council | Method for determining if deterioration in structural integrity of a pressure vessel, a pressure vessel, and a structural integrity testing apparatus therefor |
US7435232B2 (en) * | 2003-09-05 | 2008-10-14 | William Marsh Rice University | Noninvasive tissue assessment |
JP2006084241A (en) * | 2004-09-14 | 2006-03-30 | Japan Atom Energy Res Inst | Diagnosing method and apparatus for spallation neutron source mercury target container |
CN1869679B (en) * | 2005-10-10 | 2011-05-11 | 四川升拓检测技术有限责任公司 | Technology for reducing elastic wave signal testing error using two-direction vibrations |
EP2278927A2 (en) * | 2008-04-25 | 2011-02-02 | Downey, Earl C. | Laparoscopic surgical instrument |
ES2600677T3 (en) | 2010-06-19 | 2017-02-10 | Perimetrics, Llc | System and procedure for determining the structural characteristics of an object |
US9869606B2 (en) | 2011-06-18 | 2018-01-16 | Perimetrics, Llc | System and method for determining structural characteristics of an object |
CA2859589C (en) | 2011-12-16 | 2019-07-09 | Perimetrics, Llc | System and method for determining structural characteristics of an object |
CN105547452B (en) * | 2016-02-25 | 2018-08-31 | 江苏祺洋航碳纤科技有限公司 | Three axis amplitude measuring instrument of carbon badminton racket |
JP7148520B2 (en) * | 2016-12-30 | 2022-10-05 | ペリメトリクス,インク. | Systems and methods for determining structural features of objects |
TWI660190B (en) * | 2017-03-15 | 2019-05-21 | 國立臺灣科技大學 | Post-quake diagnostic method and post-quake diagnostic apparatus |
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US3014364A (en) * | 1956-06-25 | 1961-12-26 | Lockheed Aircraft Corp | Means for testing bond strength |
US3106838A (en) * | 1959-12-14 | 1963-10-15 | Lockheed Aircraft Corp | Welded joint tester |
US3153338A (en) * | 1961-11-22 | 1964-10-20 | Kleesattel Claus | Resonant sensing devices |
US3531982A (en) * | 1968-03-26 | 1970-10-06 | Nasa | Apparatus for the determination of the existence or non-existence of a bonding between two members |
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US3794236A (en) * | 1973-05-07 | 1974-02-26 | Raytheon Co | Monitoring and control means for evaluating the performance of vibratory-type devices |
US4031744A (en) * | 1975-04-25 | 1977-06-28 | Kaman Aerospace Corporation | Method and apparatus for analyzing a damped structural specimen |
DE2522362C3 (en) * | 1975-05-21 | 1980-04-10 | Gaddum Qualimeter Gmbh & Co Pruefmaschinen Kg, 3031 Ahlden | Method and device for measuring material properties of a sample |
FR2435029A1 (en) * | 1978-08-31 | 1980-03-28 | Oreal | METHOD FOR MEASURING AT LEAST ONE MECHANICAL CHARACTERISTIC OF AN ELASTIC MATERIAL AND APPARATUS THEREOF |
DE2934928C2 (en) * | 1979-08-29 | 1984-03-29 | Siemens AG, 1000 Berlin und 8000 München | Device for permanent monitoring of a part of a plant in operation |
GB8309030D0 (en) * | 1983-03-31 | 1983-05-11 | Cawley P | Testing of structures by impact |
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US5210704A (en) * | 1990-10-02 | 1993-05-11 | Technology International Incorporated | System for prognosis and diagnostics of failure and wearout monitoring and for prediction of life expectancy of helicopter gearboxes and other rotating equipment |
GB2254425B (en) * | 1991-04-03 | 1995-07-05 | Honda Motor Co Ltd | Defect detecting method and apparatus |
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US5305645A (en) * | 1992-05-04 | 1994-04-26 | The Center For Innovative Technology | Dynamic measurement of material strength and life under cyclic loading |
US5402781A (en) * | 1993-03-03 | 1995-04-04 | Washington University | Method and apparatus for determining bone density and diagnosing osteoporosis |
US5476009A (en) * | 1993-03-03 | 1995-12-19 | Washington University | Method and apparatus for determining material fatigue by measuring damping factors |
-
1993
- 1993-03-03 US US08/025,940 patent/US5476009A/en not_active Expired - Fee Related
-
1994
- 1994-03-01 AU AU62520/94A patent/AU6252094A/en not_active Abandoned
- 1994-03-01 DE DE69412829T patent/DE69412829T2/en not_active Expired - Fee Related
- 1994-03-01 WO PCT/US1994/002172 patent/WO1994020826A1/en active IP Right Grant
- 1994-03-01 ES ES94909835T patent/ES2123125T3/en not_active Expired - Lifetime
- 1994-03-01 EP EP94909835A patent/EP0704050B1/en not_active Expired - Lifetime
- 1994-03-01 AT AT94909835T patent/ATE170287T1/en not_active IP Right Cessation
- 1994-03-01 JP JP6520095A patent/JPH08507378A/en active Pending
- 1994-03-01 CA CA002157364A patent/CA2157364A1/en not_active Abandoned
-
1995
- 1995-06-07 US US08/473,728 patent/US5614674A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
ATE170287T1 (en) | 1998-09-15 |
DE69412829D1 (en) | 1998-10-01 |
US5476009A (en) | 1995-12-19 |
US5614674A (en) | 1997-03-25 |
AU6252094A (en) | 1994-09-26 |
EP0704050A1 (en) | 1996-04-03 |
WO1994020826A1 (en) | 1994-09-15 |
ES2123125T3 (en) | 1999-01-01 |
EP0704050A4 (en) | 1995-11-21 |
JPH08507378A (en) | 1996-08-06 |
CA2157364A1 (en) | 1994-09-15 |
DE69412829T2 (en) | 1999-04-22 |
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